1. Field of the Invention
The present invention relates to apparatus for improving the room-heating efficiency of a fireplace, and more particularly concerns apparatus having an enclosure adapted to be positioned below burning logs and through which heated air can be blown for useful effect.
2. Description of the Prior Art
Many homes and offices are equipped with fireplaces to provide heat during cold weather. The heat is generated by burning logs or log substitutes within the fire chamber of the fireplace. Radiant heat from the burning material heats the room. Although the radiant heat generated by the burning material supplies heat to the room, the majority of the heat thus generated is discharged through the flue of the fireplace and out through the chimney in the form of heated gases. These gases must be discharged for safety reasons and cannot be vented into the home or office without seriously endangering the occupants thereof. It would accordingly be highly desirable to have a device which could capture at least a portion of the otherwise lost radiant heat and heat from the combustion gases and transfer such captured heat into the home or office. Because many existing fireplaces could benefit from such a device, it would be a further benefit if the device could be easily installed within an existing fireplace.
The use of devices which capture heat from a fireplace in the form of heated air and direct such heated air forwardly into the room having the fireplace is well known. Such devices generally employ a plenum chamber positioned below the burning logs, and an electrically operated blower which advances air through the chamber, causing the air to be heated by heat exchange effect and exit into the room. Examples of such devices are disclosed in U.S. Pat. Nos. 4,074,681; 5,038,754; 5,904,137; 6,145,502; 6,463,926; 7,111,623 and 7,258,116.
In most instances, the plenum chamber is intended to rest upon the floor of the fireplace and is comprised of conduits arranged in a horizontal profile extending the width of the fireplace in a manner enabling the chamber to serve as a grate for supporting the logs. Fabrication of the assemblage of conduit components is expensive, especially where a high degree of tortuosity is employed to increase the total heat transfer surface area. Furthermore, multi-component heat exchange units cause problems with respect to the removal of residual ash and debris from the fireplace, and if such debris is not removed, it seriously impairs the heat exchange efficiency of the unit. Components such as tubing, which may provide high efficiency of heat exchange, generally lack durability in fireplace conditions.
It is thus an object of the invention to provide a fireplace heat exchanger that can capture at least a portion of the heat from the burning material within a fireplace and transfer the captured heat into a room.
It is a further object of the invention to provide a fireplace heat exchanger that can be easily installed within an existing fireplace.
It is another object of the present invention to provide a fireplace heat exchanger which does not interfere with the removal of debris from the fireplace.
It is a still further object of this invention to provide a fireplace heat exchanger of the aforesaid nature which is of durable construction and amenable to low cost manufacture.
These objects and other objects and advantages of the invention will be apparent from the following description.